Authentication methods play an important role in distinguishing genuine objects from counterfeit objects. Objects such as documents, textile items, woodcrafts, automotive parts, consumer products and so on are subject to forgery through replication/duplication. In most of the cases, it is difficult to check whether an object is authentic or not, by means of manual inspection. Counterfeit objects compromise quality and hence, the customer who purchases a counterfeit object is not obtaining the value for her investment. Forging also raises security related issues.
An existing system to prevent forgery of objects such as documents uses digital watermarks to authenticate objects. When a digital watermark is used for authentication purposes, it is made invisible such that it can be read only if the location of the digital watermark is known. Also, the nature of the information embedded should be known. But with the latest forgery techniques, it is possible to effectively duplicate the digital watermark, making the system ineffective.
In another existing technique for preventing forgery, bar codes are associated with the objects for the purpose of authentication. A bar code is an optical machine readable representation of data. The data present in a bar code shows details about the object to which the bar code is attached. Special optical scanners called bar code readers are required to scan bar codes. The problem with the technique of using only bar codes is that the bar codes can be easily reproduced and/or copied which makes the system vulnerable for counterfeiting. Further, the special bar code readers are expensive and require an additional computing device to decode the information.
Another existing system for preventing forgery and duplication of objects uses a combination of nanoparticle spray and bar code. The problem with this method is that a dedicated magnetic reader is required for reading the nanoparticle pattern and an optical reader is required for bar code reading. The use of two readers adds to the overall cost of the system.
In another existing method for preventing object counterfeiting, biometric measurement techniques such as fingerprint and/or iris scanning are used. Biometric scanners are expensive devices and use of such scanners adds to the cost of the system.
Another existing technique used for object authentication uses near field communication (NFC) technique. NFC technique allows simplified transactions and data exchange between two devices in close proximity to each other. Special NFC chips are to be embedded in objects so as to enable communication between them and a reading device. Object identification codes could be stored and read from the NFC chips. The requirement of dedicated NFC chips makes the system expensive.
Another existing technique for prevention of object counterfeiting uses RFID based techniques. An RFID system uses radio waves for the purpose of identification and tracking of object. An RFID tag is formed and is attached to the object to be tracked. A RFID reader could read object identification codes from the tags. RFID tags and readers are expensive and add to the total cost of the system.
Another existing system for authentication is called Laser Surface Authentication (LSA) where the system reads the surface of the object and obtains a unique digital serial code. An issue with this system is that the laser based identification scheme requires dedicated system components which add to the cost of the system.
Another existing system for authentication uses a technology called Physical Unclonable Function (PUF). PUF implements a challenge-response kind of authentication. This technology is more suited for silicon chips. An issue associated with the PUF technology is that it lacks stability, with changes in environmental parameters such temperature, pressure and humidity. The physical properties on which this technology depends also change with aging.